<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            /*width: 200px;*/
            /*height: 200px;*/
            background-color: #F00;

            display: inline-block;
        }
        div:first-child{
            /*margin-right: 20px;*/

            background-color: green;

            line-height: 50px;
            display: inline-block;
        }
        span{
            width: 300px;
            height: 300px;
            display: inline-block;
        }
    </style>
</head>
<body>
    <div>aaaaaa</div>
    <div>aaaa</div>
</body>
</html>